Telephone



M. c. A. 'LAT OUR.

v TELEPHONE. I

APPLICATION FILED APR.18, 1916.

1,421,015, Patented Ju e 27,1922

PATENT OFFICE.

MARIUS C. .LATOUR, OF PARIS, FRANCE.

TELEPHONE.

Specification of Letters Patent.

I Application fi1ed Apri1'18, 1916. Serial No. 92,033.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. In, 1313.)

v To all whom it may concern.

Beit known that I, MARIUS C. A. LA'roUR, engineer, resldlng in Paris, France, 22 Rue Tocqueville, have invented new and useful Improvements in Telephones, for which I have filed applications in France, asfollows: December 28, 1914, patented June 6, 1918, No. 488,190; March 1,1915, patented March 27, .1919, No. 20,803, and March 9, 1915, patented March 27, 1919, No. 20,804.

This invention relates to improvements in telephones and has for its object to pro -tect the telephone system .against losses of current.

\Vith this end in view the entire stationary or fixed part of the magnetic circuitof the telephone system is made of a plurality of segments of sheet metal cut and assembled with an insulating metal between the single segments so that the whole has the appearance of a foliated block without magnetic connections.

In the accompanying drawing:

Fig. 1 shows one of the segments for the stationary part of the magnetic circuit.

Fig. 2 is a similar view with an inductance in series with a source of current.

Fig. 3 is a similar view with a transformer.

Fig. 4 shows the transformer as automatically operating. 7

Fig. .5 is a View similar to F ig. 1 with the inductance in shunt.

Fig. 6 is a top plan view of a diaphragm.

Fig. 7 shows a diaphragm provided with slots.

Fig. 8 shows a modified form of diaphragm constituted by threads of soft iron juxtaposed .between two paral1elthreads m w and 3 y. i

Fig. 9 illustrates the use of the magnetic auxiliary circuit.

Fig. 10 shows the shape of current coming from a receiving wireless station having a telephone according to the present .invention.

Fig. 11 shows the arrangement of the exciter coil in fractions.

In the drawing, F represents one of the segments of sheet metal forming the electromagnet of the receiver, B is the telephone wire and P represents the diaphragm, while 6 is the source of current for the permanent excitation of the magnetic circuit.

The losses of line currents by the appearance of so called Foucault currents in Patented June 2'7, 1922.

the diaphragm is avoided the followmg manner: 4

The F oucalt currents are produced within the field created by the action of the poles of the magnets upon the inner face of the diaphragm. Therefore, the diaphragm according to the present invention is provided with incisions along a direction parallel to an axis'passing through botn poles, as for instance shown in Figure 7, which represents the telephone in plan view seen from the top of the diaphragm in this figure the incisions of the diaphragm and the projections of the foliated polar pieces being shown. The size of the incisions is very small and moreover they are adapted to be closed by a speci l substance capable of magnetic attraction so as to prevent any current of air passing through such incisions.

In the modified form ofdiaphragm shown in Fig. 8 the diaphragm is formed by a plurality of juxtaposed soft iron threads disposed between two parallel suspension thread: 00 a" and 3/ y. In such a telephone,

thanks to the permanent excitation by the continuous current of the magnetic circuit, the diaphragm maybe acted upon by much stronger inductions than those usually employed, precautions however, must be taken to prevent the diaphragm from sticking to the pole pieces.

This result can be obtained by letting a certain pressure act upon the diaphragm, a pressure which is higher than the atmospheric pressure and which is capable of counterbalancing totally or least in part the magnetic attraction permanently exerted up on the same.

The telephone forming the object of the present invention can be used everywhere where the ordinary telephones are used. It is sufficient to provide a surce of continuous current which is capable of furnishing the necessary current for the excitation of the coil B, which is provided for in Figure 2 by means of providing a branch coil in connection with the coil B. It will be understood that some provision must be made for preventing the line current from passing through this branch coil and I accordingly connect the inductance Z in series with the source of current 6, which overcomes this difiiculty.

According to the illustration in Fig. 3

current.

ancing the self induction of the coil B for the line currents without thereby impeding the circulation of the continuous exciter Therefore, as shown in Fig. 5 in derivation with the capacity 0 an appropriate inductance Z is arranged. The capacity will allow the line current to pass while the inductance will let the continu ous exc'iter current pass. I

If the invention is to be applied to wire- I less telephonythe same need only be substituted for the telephones actually used in the detector currentand in cases where a battery is used the same may be employed for the excitation of the telephone,

In Wireless telephony the telephone according to the present invention, thanks to its construction Without permanent magnet permits its use in theheterodyne system of wireless te-legraphy for receiving direct without the employment of a detector. It is sufficient to substitute for this purpose in the telephone illustrated in Fig. 1 for the source of continuous current, a local generator of local waves.

WhatI claim is:

1. A telephone receiver having a coilcarrying the telephonic current, an electromagnet excited by said coil, sa d electromagnet having a magnetic circuit comprising a fixed portion associated with said coil.

to provide a permanent field and a movable diaphragm, having slits extending in a direction from pole to pole of the fixed portion for eliminating eddy current losses.

2, A telephone receiver having a coil carrying the telephonic current, an electromagnet excited by said coil,.said electromagnet havin a magnetic circuit comprising a fixed portion of laminated soft iron associated with said coil to provide a permanent field, and a movable dia'phragmhaving slits extending in a direction from pole to pole of the fixed portion for eliminating eddy current losses.

3. A telephone receiver having a coilcarrying the telephonic current. an electromagnet exc ted by S3i1d COll, said electromagnet having a magnetic circuit comprising a fixed portion associated with said coil to provide a permanent field and a movable diaphragm of juxtaposed iron wire extending in a direction from pole to pole of the fixed portion for the purpose of reducing eddy current losses.

4:. A telephone receiver having a coil carrying the telephonic current, an electromagnet excited bysaid coil,-sa1d electro- .magnet having a magnetic circuit comprising a fixed portion associated with said coil to provide mpermanent field and a movable diaphragm having slits extending in a direction from pole to pole of the fixed portion for eliminating eddy current losses, said slits being substantially closed to substantially prevent passage of air therethrough.

5. A telephone receiver having a coil carrying the telephonic current, an electromagnet excited by, said coil, said electroma-gnet having a magnetic circuit comprising a fixed portion of laminated soft iron associated with said coil to provide a permanent field, and a movable diaphragm having slits-extending in a direction from pole to pole of the fixed portion for eliminating eddy current losses said slits being substantially closed to substantially prevent passage of air therethrough.

6. A telephone receiver having a coil carrying ,theteleph-onic current, an electromagnet excited by said coil, said electromagnet having a magnetic circuit comprising a fixed portion associated with said coil to provide a permanent field and a movable diaphragm, having slits extending in a. direction from pole to pole of the fixed portion for eliminating eddy current losses, a portion of said magnetic circuit being excited to substantially the saturation point.

v 7. A telephone receiver having a coil carrying the telephonic current, an electromagnet excited by said coil, said electromagnet having a magnetic circuit comprising a fixed portion associated with said coil to provide a permanent field and a movable diaphragmhaving slits extending in a direction from pole to pole of the fixed portion for eliminating eddy current losses, and means for damping'the diaphragm.

In testimony whereof I have signed my name to this specification in the presence of two Witnesses.

MAR-IUS C. A. LATOUR.

Witnesses:

J OSEPH BETHENOOF, CARLTON HURST. 

